Posted
by
timothy
on Sunday May 04, 2014 @08:35AM
from the new-number-between-7-and-8 dept.

From Motherboard comes this description of what may turn out to be the newest entry on the periodic table,
newly synthesized element 117, created by researchers at the GSI Helmholtz Centre for Heavy Ion Research of Darmstadt, Germany, and described in results published this week in Physical Review Letters. From the article:
"Element 117 has been temporarily given the very literal name ununseptium (one-one-seven in Latin), and will only honored with a real name once the the International Union of Pure and Applied Physics and Chemistry (IUPAPC) confirms its synthesis at the GSI accelerator. Ununseptium is 40 percent heavier than lead, making it on par with the heaviest atoms ever observed. ... Its properties seem to confirm that the existence of the so-called “island of stability”—a theory suggesting that the half-lives of superheavy isotopes will lengthen as their atomic numbers increase further away from uranium. Any element with an atomic number greater than 103 is considered superheavy (or in the 'transactinide class,' if you prefer the scientific jargon). Transactinides can only be observed artificially in a laboratory, and synthesizing them is no easy task."
Note: that "real name" process isn't a mere formality; just a few years ago, another attempt to synthesize a 117th element looked promising enough to be declared done, but could not be confirmed with the IUPAPC's tests.

Just because the atoms are 40% heavier doesn't mean the bulk material (if ignoring half-life issues) will be 40% denser. Osmium is still 10% denser than uranium, and uranium is 30% denser than californium.

The "40% heavier" actually refers to atomic weight, not density. By density, Tungsten is ~70% heaver than lead, Depleted Uranium about 68%. Tungsten's atomic wight is actually ~10% lighter than Lead's. Bulk density is about arrangement of the electrons and the resulting packing of atoms in the solid.